This invention relates in general to flow control devices and in particular to a new and useful gas flow control device for a gas sampler apparatus.
The present invention has application to the control of all fluids which require a reduction of flow or a turnoff of the flow due to certain temperature changes. The invention has particular application in the construction of a gas analyzer which uses heated sampling systems to prevent liquid condensation in the system and that draw a gas through the system by using an aspirating gas such as air to effect the flow. It is desirable with such devices to interrupt the aspirator gas flow when the sampling components temperatures fall below the dew point of the sample gas. Conventional means use a temperature sensor and a control with a gas solenoid valve which controls the aspirating air stream. Such an arrangement involves expensive electrical circuitry and connections and piping and frequently limits its applicability due to the ambient condition effects on the valve and electrical components.